Add Hybrid and Gruvbox themes

[parkerault]

This PR depends on #2083

Add a port of the Hybrid theme: https://github.com/w0ng/vim-hybrid

Screenshots:

...and also Gruvbox: https://github.com/morhetz/gruvbox

Screenshots:

[parkerault]

@bryphe I set the base branch to your WIP for baseVimBackground so they can get released together. Let me know if you would rather set it up some other way.

[codecov]

Codecov Report

Merging #2088 into bryphe/theming/specify-background-theme will increase coverage by 0.02%.
The diff coverage is 87.5%.

@@                             Coverage Diff                             @@
##           bryphe/theming/specify-background-theme    #2088      +/-   ##
===========================================================================
+ Coverage                                    36.79%   36.81%   +0.02%     
===========================================================================
  Files                                          288      288              
  Lines                                        11424    11417       -7     
  Branches                                      1540     1537       -3     
===========================================================================
  Hits                                          4203     4203              
+ Misses                                        6984     6977       -7     
  Partials                                       237      237

Impacted Files	Coverage Δ
...rowser/src/Services/WindowManager/WindowManager.ts	66.35% <100%> (ø)	⬆️
...rowser/src/Services/Explorer/ExplorerFileSystem.ts	76.92% <85.71%> (ø)	⬆️
browser/src/Services/Themes/ThemeManager.ts	60.52% <0%> (ø)	⬆️
browser/src/Editor/NeovimEditor/NeovimEditor.tsx	9.4% <0%> (+0.13%)	⬆️

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[bryphe]

@parkerault - these look great! Nice work 👍 I'm going to have to take the Hybrid theme for a test drive..

@bryphe I set the base branch to your WIP for baseVimBackground so they can get released together. Let me know if you would rather set it up some other way.

Perfect, that makes sense! I'm just wrapping it up now. I added a CiTest to validate that background gets set appropriately - think it's almost good to go.

[parkerault]

@bryphe check out gruvbox; you might not like the colors, but the language support is excellent. I am considering using it as a template for all other themes.

[bryphe]

Cool, the syntax highlighting does look much more useful with gruvbox 👍 Showcases the textmate highlighting in a better way.

I brought in #2083 , so you can change the base back to master - and I'll bring this in. Looking forward to trying these out!

[parkerault]

@bryphe GTG

[bryphe]

Sweet! Thanks a lot for working on these, @parkerault 👍 Bringing them in now!